Underframes for longwall mineral mining machines

ABSTRACT

An underframe for a longwall mineral mining machine has a hollow deck which forms a guide duct for dust laden air which is drawn from the region around the cutter head and passed via the guide duct to a layer of filter material which removes the dust before the relatively dust free air is discharged into the mine atmosphere.

United States Patent Agnew 1 Oct. 24, 1972 [54] UNDERFRAMES FOR LONGWALL [56] References Cited MINERAL MINING MACHINES UNITED STATES PATENTS [72] inventor: James Malcolm Agnew, Burtonuponfrrent [73] Assignee: EOoaId lndsusti'y d(Patents) Limited, Primary Emmt-ner Emest Purser n ng an Attorney-Stevens, Davis, Miller & Mosher [22] Filed: June 28, I971 21 Appl. No.: 157,342 [57] ABSTRACT An underframe for a longwail mineral mining machine has a hollow deck which forms a guide duct for dust [30] Foreign Apphcauon pniority Data laden air which is drawn from the region around the July l7, i970 Great Britain ..34,829/70 cutter h d d passed ia the guide duct to a layer of filter material which removes the dust before the rela- ISZ] US. Cl .299/46, 299/12 tively dust free air is discharged into h i [51 int. Cl. ..E21c 35/22 mosphere [58] Field of Search ..299/i2, 45, 46

9 Claims, 1 Drawing Figure h-- wfl 40 w r 39 K y E P l 1 14 lb x b Lib A I e A e T J L m a 18 UNDERFRAMES FOR LONGWALL MINERAL MINING MACHINES This invention relates to support underframes for use with longwall mineral mining machines and in particular the invention relates to underframes for use with such machines when provided with apparatus for extracting airborne dust particles and/or methane gas from the vicinity of a cutter head of the machine. Support underframes support the base of the body of the machine and are adapted to travel along an armored conveyor extending along the longwall face.

As the number of mineral mining machines installed on a mineral face increases, the accumulative amount of airborne dust generated by these machines correspondingly increases and the known conventional airborne dust suppressions techniques e.g. sprays of dust suppression fluid, usually have been found inadequate.

Known coal mining machines used on longwall coal faces have been provided with apparatus for extracting airborne dust particles and/or methane gas from the vicinity of the cutter head of the machine. Such apparatus comprised an air flow guide duct and a device for inducing air flow in the guide duct away from the cutter head. Unfortunately, because of the limited space available on a longwall face the known guide ducts which were positioned above or by the side of the machine, have been prone to damage and as a result the use of longwall mining machines provided with dust extraction apparatus has been limited to a few installatrons.

An object of the present invention is to overcome the above mentioned disadvantage by providing an improved air flow guide duct.

According to the invention an underframe for a longwall mineral mining machine comprises a hollow deck upon which the machine can be supported, and means which in operation enable the underframe to be mounted on, for movement along, an armored conveyor extending along a longwall face, the hollow deck providing an air flow guide duct extending along the underframe.

Preferably, the end of the underframe adjacent to the outlet from the guide duct supports an assembly for inducing air flow along the duct, the inlet end of the guide duct being connectable to a further duct extending towards the cutter head of the machine.

The assembly may comprise a fan which draws the air flow through a layer of filter material, as for example, a layer of synthetic fiber material.

The assembly may comprise an inlet chamber having a larger cross-sectional area than the guide duct, and means for facilitating the removal of the dust particles which have been deposited in the chamber before reaching the filter material.

The underframe may comprise a further chamber having a larger cross-sectional area than the guide duct and having means facilitating the removal of the dust particles which have been deposited in the further inlet chamber before reaching the guide duct.

By way of example only, one embodiment of the invention will now be described with reference to the accompanying drawing which shows a side view, partly in section, of a support underframe supporting a longwall shearer mining machine and constructed in accordance with the present invention.

The drawing shows a. ranging drum shearer 2 having an arm 4 which supports a cutter drum 6. The shearer 2 is supported on a support underframe 8 having means in the form of four guide shoes 10 (only two of which are shown) which enable the underframe 8 to be mounted on, for movement along, an armored conveyor 12 extending along the longwall face.

The underframe 8 has a hollow deck 14 formed by an upper plate 16 which supports the shearer 2 and a lower plate 18 to which the shoes 10 are attached. The sides of the hollow deck 14 are closed by side walls, both ends of the hollow deck 14 being open so that the hollow deck forms a through guide duct extending the length of the shearer 2.

The lower plate 18 extends at one end beyond the upper plate 16 and supports an assembly 20 which in operation induces an air flow in the direction indicated by arrow X along the guide duct extending along the length of the underframe 8 and formed by the follow deck 14. The assembly 20 comprises a centrifugal fan 22 driven via a belt and two pulleys by a motor 24, and an inlet chamber 28 which has a larger cross-sectional area than the guide duct 14 and which has an open sided drawer 29 which may be removed from the chamber 28 by lifting pin 30 and pulling the handle 3 1.

A frame 32 secured to upper portions of the sides of the drawer 29 supports a layer 26 of filter material as for example a layer of synthetic fiber material.

Guides 33 are secured to the frame 32 to ensure that the air flow is evenly distributed over the whole area of the filter 26.

At the end of the underframe 8 remote from the assembly 20, the guide duct 14 is connected to a curved duct 34 leading to a chamber 36 having a larger crosssectional area than the guide duct 14 and having means (not shown) facilitating cleaning of the chamber 36.

Flexible ducting 38 extends from the chamber 36 to shrouding curtains 40 which partially surround the cutter head 6 and which have flexible upper strips 41 bearing against the roof of the seam. The flexible strips 41 ensure that the curtains 40 remain in contact with the roof when the arm 4 is ranged up and down during operation of the shearer. The curtains 40 are secured to the arm 4 by a U shaped frame assembly 39.

In operation as the shearer 2 cuts along the face, the shrouding curtains 40 segregate the air flow in the vicinity of the cutter head 6 from the main ventilation air flow along the face, and thereby, prevent airborne dust particles from entering the ventilation air flow. When the fan 22 is operative an air flow is induced away from the cutter head 6 along the ducts 38, 34 and 14 and through the chambers 36 and 28 towards the filter 26.

Upon reaching the chamber 36 the air flow velocity is reduced and, therefore, the larger dust particles are deposited from the air flow. As the chamber 36 has a larger cross-sectional area than the guide duct 14 this ensures that the air flow velocity within the duct 14 is sufficient to ensure no dust particles are deposited in the duct 14.

As previously mentioned the chamber 36 is provided with means for example a door, for facilitating the removal of the dust particles from the chamber 36 when found necessary.

Upon reaching the cham er 28 the air flow velocity is further reduced and more of the larger dust particles are deposited in the drawer 29 of the chamber 28.

The air flow is then drawn through the filter 26 where the small dust particles are arrested. The relatively dust free air is then discharged through an outlet 42 into the ventilation air flow.

The filter 26 can be replaced when it becomes clogged up with dust particles by opening the drawer 29 and exchanging the old filter 26 for a clean one.

The necessary frequency of the replacement of the filter 26 and the removing of the dust particles from the chambers 28 and 36 can only be determined by experience at any one installation and will depend upon the dust make and amount of mineral cut.

In a typical arrangement with the fan 22 inducing an air flow of I000 cubic feet per minute the guide duct 14 would have a cross-sectional area of about 38 square inches.

It can be seen from the above description that the invention enables a longwall mineral mining machine to be provided with dust extraction apparatus without having a large cumbersome guide duct prone to damage.

Further, the invention tends to prevent the possible build up of methane gas around the cutter drum 6 and, therefore, tends to reduce the danger of an explosive mixture of the gas being ignited by the cutter tools on the rotating drums as they strike the mineral face.

In modified arrangements the assembly 20 comprises venturi scrubbers instead of the filter 26.

In further modifications of the invention the chamber 36 is dispensed with. In such modifications the inlet of the duct 38 may be relatively remote from the cutter head 6 so that the larger particles of dust settle out from the air flow before it enters the duct 38. For example, the inlet may be positioned five feet from the cutter head on the down stream side with respect to the mine ventilation current.

In still further modifications of the invention the guide 33 may be dispensed with.

I claim:

1. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, and means which in operation enable the underframe to be mounted on, for

movement along, an armored conveyor extending an assembly for inducing air flow along the duct, the assembly being supported on the underframe adjacent to the air-outlet end of the guide duct.

3. An underframe as claimed in claim 2, in which a layer of filter material and a fan are provided in the assembly, the fan being arranged to draw the air flow through a layer of filter material.

4. An underframe as claimed in claim 3, in which guides are provided in the assembly to ensure that the air flow is distributed over substantially the whole area of the filter material.

5. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, means which in operation enable the underframe so be mounted 03, for movement along, an armore conveyor exten mg along a longwall face, the hollow deck providing an air flow guide duct extending along the underframe, and an assembly which is for inducing the air flow along the duct which is supported on the underframe adjacent to the air-outlet end of the duct, and which comprises an inlet chamber having a larger cross-sectional area than the guide duct.

6. An underframe as claimed in claim 5, comprises means for facilitating the removal of dust particles which in operation have been deposited in the chamber.

7. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, and which provide an air flow guide duct extending along the underframe, an assembly for inducing the air flow along the duct, and a chamber arranged intermediate the cutter head of the machine and the air-inlet end of the guide duct, the chamber having a larger cross-sectional area than the guide duct.

8. An underframe as claimed in claim 7, comprising a further guide duct extending from the chamber towards the cutter head of the mining machine.

9. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, and which provides an air flow guide duct extending along the underframe, an assembly which is for inducing the air flow along the duct and which comprises an inlet chamber, and a second chamber arranged intermediate the cutter head of the machine and the air-inlet end of the guide duct, both said chambers having larger cross-sectional areas than the guide duct. 

1. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, and means which in operation enable the underframe to be mounted on, for movement along, an armored conveyor extending along a longwall face, the hollow deck providing an air flow guide duct extending along the underframe.
 2. An underframe as claimed in claim 1, comprising an assembly for inducing air flow along the duct, the assembly being supported on the underframe adjacent to the air-outlet end of the guide duct.
 3. An underframe as claimed in claim 2, in which a layer of filter material and a fan are provided in the assembly, the fan being arranged to draw the air flow through a layer of filter material.
 4. An underframe as claimed in claim 3, in which guides are provided in the assembly to ensure that the air flow is distributed over substantially the whole area of the filter material.
 5. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, means which in operation enable the underframe to be mounted on, for movement along, an armored conveyor extending along a longwall face, the hollow deck providing an air flow guide duct extending along the underframe, and an assembly which is for inducing the air flow along the duct which is supported on the underframe adjacent to the air-outlet end of the duct, and which comprises an inlet chamber having a larger cross-sectional area than the guide duct.
 6. An underframe as claimed in claim 5, comprises means for facilitating the removal of dust particles which in operation have been deposited in the chamber.
 7. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, and which provide an air flow guide duct extending along the underframe, an assembly for inducing the air flow along the duct, and a chamber arranged intermediate the cutter head of the machine and the air-inlet end of the guide duct, the chamber having a larger cross-sectional area than the guide duct.
 8. An underframe as claimed in claim 7, comprising a further guide duct extending from the chamber towards the cutter head of the mining machine.
 9. An underframe for a longwall mineral mining machine, comprising a hollow deck upon which the machine can be supported, and which provides an air flow guide duct extending along the underframe, an assembly which is for inducing the air flow along the duct and which comprises an inlet chamber, and a second chamber arranged intermediate the cutter head of the machine and the air-inlet end of the guide duct, both said chambers having larger cross-sectional areas than the guide duct. 